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Valves of the heart
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When a heart is functioning normally, blood is pumped through its four chambers with the help of a series of heart valves.
These valves open and close in a way that allows blood to flow only one way. The pulmonary valve allows oxygen-poor (blue) blood to flow from the lower right chamber of the heart, called the right ventricle, to a large artery called the pulmonary artery.
The pulmonary artery sends the oxygen-poor blood into the lungs where it is enriched with oxygen.
The pulmonary valve has three leaflets that function like a one-way door, allowing blood to flow forward into the pulmonary artery, but not backward into the right ventricle. Pulmonary stenosis, a congenital (present at birth) heart defect, occurs when the pulmonary valve is unable to open completely.
With pulmonary stenosis, problems with the pulmonary valve make it harder for the leaflets to open and permit blood to flow forward from the right ventricle to the lungs. In children, these problems can include:
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- a valve that only has one or two leaflets instead of three
- a valve that has leaflets that are partially fused together
- a valve that has thick leaflets that do not open all the way
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Pulmonary Stenosis
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Pulmonary stenosis may be present in varying degrees, classified according to how much obstruction to blood flow is present. A child with severe pulmonary stenosis could be quite ill, with major symptoms noted early in life. A child with mild pulmonary stenosis may have few or no symptoms, or perhaps none until later in adulthood. A moderate or severe degree of obstruction can become worse with time.
Pulmonary stenosis is a component of half of all complex congenital heart defects. Pulmonary stenosis is the second most common congenital heart defect, composing 5 to 10 percent of all cases.
For in-depth visual and audio information on this condition, visit the Children's Hospital Boston Multimedia Library.
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Congenital pulmonary stenosis occurs due to improper development of the pulmonary valve in the first eight weeks of fetal growth. It can be caused by a number of factors, though most of the time this heart defect occurs sporadically (by chance), with no clear reason evident for its development.
Some congenital heart defects may have a genetic link, either occurring due to a defect in a gene, a chromosome abnormality or environmental exposure, causing heart problems to occur more often in certain families.
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Mild pulmonary stenosis may not cause any symptoms. Problems can occur when pulmonary stenosis is moderate to severe, including the following:
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- The right ventricle has to work harder to move blood through the tight pulmonary valve. Eventually, the right ventricle is no longer able to handle the extra workload, and it fails to pump forward efficiently. Pressure builds up in the right atrium, and then in the veins bringing blood back to the right side of the heart. Fluid retention and swelling may occur.
- There is a higher than average chance of developing an infection in the lining of the heart known as bacterial endocarditis.
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The following are the most common symptoms of pulmonary stenosis. Each child may experience symptoms differently. Symptoms may include:
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- heavy or rapid breathing
- shortness of breath
- fatigue
- rapid heart rate
- swelling in the feet, ankles, face, eyelids and/or abdomen
- fewer wet diapers or trips to the bathroom
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The symptoms of pulmonary stenosis may resemble other medical conditions or heart problems. Always consult your child's physician for a diagnosis.
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Your child's physician may have heard a heart murmur during a physical examination and referred your child to a pediatric cardiologist for a diagnosis. A heart murmur is simply a noise caused by the turbulence of blood flowing through the obstruction from the right ventricle to the pulmonary artery. Symptoms your child may experience will also help with the diagnosis.
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A pediatric cardiologist specializes in the diagnosis and medical management of congenital heart defects, as well as heart problems that may develop later in childhood. The cardiologist will perform a physical examination, listening to the heart and lungs, and make other observations that help in the diagnosis. The location within the chest that the murmur is heard best, as well as the loudness and quality of the murmur (harsh, blowing, etc.) will give the cardiologist an initial idea of which heart problem your child may have. Other tests are needed to help with the diagnosis, and may include the following:
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- Chest X-ray — A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones and organs onto film.
- Electrocardiogram (ECG or EKG) — A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias) and detects heart muscle stress.
- Echocardiogram (echo) — A procedure that evaluates the structure and function of the heart by using sound waves, recorded on an electronic sensor, that produce a moving picture of the heart and heart valves.
- Cardiac Catheterization — A procedure that gives very detailed information about the structures inside the heart. Under sedation, a small, thin, flexible tube (catheter) is inserted into a blood vessel in the groin and guided to the inside of the heart. Blood pressure and oxygen measurements are taken in the four chambers of the heart, as well as in the pulmonary artery and aorta. Contrast dye is injected to more clearly visualize the structures inside the heart.
- Cardiac Magnetic Resonance Imaging (MRI) — A non-invasive test that uses three-dimensional imaging technology produced by magnets to accurately determine blood flow and functioning of the heart as it is working.
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Specific treatment for pulmonary stenosis will be determined by your child's physician based on:
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- your child's age, overall health and medical history
- extent of the condition
- your child's tolerance for specific medications, procedures or therapies
- how your child's doctor expects the condition may progress
- your opinion or preference
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Mild pulmonary stenosis often does not require treatment. Moderate or severe stenosis is treated with repair of the obstructed valve. Several options are currently available.
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Some infants will be very sick and requiring care in the intensive care unit (ICU) prior to the procedure, and could possibly even need emergency repair of the pulmonary valve if the stenosis is severe. Others, who show few symptoms, will have the repair scheduled on a less urgent basis.
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Repair options include the following:
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- Balloon Dilation or Valvuloplasty — In a cardiac catheterization procedure, a small, flexible tube (catheter) is inserted into a blood vessel in the groin and guided to the inside of the heart. The tube has a deflated balloon in the tip. When the tube is placed in the narrowed valve, the balloon is inflated to stretch the area open. This procedure may be used for valvar, supravalvar, or branch types of pulmonary stenosis. Children who have undergone balloon dilation will need to follow antibiotic prophylaxis for a specific period of time after discharge from the hospital.
- Valvotomy — Surgical separation of valve leaflets that have become fused, allowing the valve leaflets to open properly.
- Pulmonary Valve Replacement: Replacement of the pulmonary valve is a surgical procedure that is often recommended in adulthood. A tissue valve (pig or human) may be used. Children who have undergone a valve replacement will need to follow antibiotic prophylaxis throughout their life.
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Most children will live healthy lives with activity levels, appetite and growth returning to normal over time. Consult your child's doctor about the specific outlook for your child.
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Complementing the Cardiovascular Program of Children's Hospital Boston is the nation's most intensive clinical and basic research program focused on pediatric heart disease. Children's is a world leader in opening new avenues of "translational research," bringing laboratory advances to the bedside and doctor's office as quickly as possible. All senior medical staff members of the Cardiovascular Program participate in clinical research activities.
Children's Hospital Boston has pioneered interventional catheterization repair of many types of congenital heart defects, including pulmonary stenosis. In many cases, this eliminates the need for open-heart surgery, allowing less pain, reduced chance of infection and shorter recovery time. Research continues on the design and creation of heart valves using a patient's own tissue.
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Contact Children's Hospital Boston Cardiovascular Program physicians for a second opinion.
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Pulmonary Stenosis
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